Marek’s disease virus as a CRISPR/Cas9 delivery system to defend against avian leukosis virus infection in chickens

Publication date: Available online 16 January 2020Source: Veterinary MicrobiologyAuthor(s): Yongzhen Liu, Zengkun Xu, Yu Zhang, Mengmeng Yu, Suyan Wang, Yulong Gao, Changjun Liu, Yanping Zhang, Li Gao, Xiaole Qi, Hongyu Cui, Qing Pan, Kai Li, Xiaomei WangAbstractThe CRISPR/CRISPR-associated protein 9 (Cas9) system is a powerful gene-editing tool originally discovered as an integral mediator of bacterial adaptive immunity. Recently, this technology has been explored for its potential utility in providing new and unique treatments for viral infection. Marek’s disease virus (MDV) and avian leukosis virus subgroup J (ALV-J), major immunosuppressive viruses, cause significant economic losses to the chicken industry. Here, we evaluated the efficacy of using MDV as a CRISPR/Cas9-delivery system to directly target and disrupt the reverse-transcribed products of the ALV-J RNA genome during its infection cycle in vitro and in vivo. We first screened multiple potential guide RNA (gRNA) target sites in the ALV-J genome and identified several optimized targets capable of effectively disrupting the latently integrated viral genome and providing efficient defense against new infection by ALV-J in cells. The optimal single-gRNAs and Cas9-expression cassettes were inserted into the genome of an MDV vaccine strain. The results indicated that engineered MDV stably expressing ALV-J-targeting CRISPR/Cas9 efficiently resisted ALV-J challenge in host cells. These findings demonstrated the CRISPR...
Source: Veterinary Microbiology - Category: Veterinary Research Source Type: research